The Night Sky (January 2019) - Usk Astronomical Society
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The Night Sky
(January 2019)
UT (Universal Time) or GMT is used this month.
The General Weather Pattern
January is often a windy month. Rain is less obvious than in the previous two months, but it usually gets colder as
the month ages. It can be very cold at night, often reaching freezing temperatures with clear skies. Snow can be
expected in cold years. Wrap up warm with a warm hat, socks and shoes and wear multiple layers of clothes. An
energy snack and a flask containing a warm drink wouldn’t go amiss.
Should you be interested in obtaining a detailed weather forecast for observing in the Usk area, log on to
https://www.meteoblue.com/en/weather/forecast/seeing/usk_united-kingdom_2635052
From Earth
The Earth is at perihelion (closest to the sun) in its elliptical orbit on the morning of the 3rd of January. The word
perihelion derives from the Greek words, peri meaning ‘near’ and Helios the Greek god of the sun.
The winter sky, dominated by Orion, presents itself due south, late in the evenings for most of this month. In the
first half of the month, the Milky Way stretches right across the sky from east to west through the zenith at the end
of evening twilight.
Artificial Satellites or Probes
Should you be interested in observing the International Space Station or other space craft, carefully log on to
http://www.heavens-above.com to acquire up-to-date information for your observing site.
Sun
Due to the equation of time the latest sunrise of the year occurs around New Year’s Eve; 30th December and the
mornings start to lighten, but you may not notice until near the end of January.
The Sun moves from Sagittarius to Capricornus on the morning of the 20th. It is also beginning its journey towards
more northerly latitudes once more, and will eventually become better placed for observing as the days get longer.
Conditions apply as to the use of this matter. © D J Thomas 2018 (N Busby)
Use appropriate, safe methods to observe the Sun and notify other members if you observe any sunspot activity.
Auroral activity is quite transient, so share information with other members ASAP.
This month’s partial solar eclipse on the 6th is not visible from the UK.
Moon
The New Moon is on 6th at about 01:30 in the constellation of Sagittarius.
The First Quarter is on 14th at about 06:45 in the constellation of Pisces.
The Full Moon is on 21st at about 05:15 in the constellation of Cancer.
The Last Quarter is on 27th at about 21:10 in the constellation of Libra.
The Moon is at perigee (nearest Earth) on the 21st and is the third closest perigee this year. The Moon is at apogee
(most distant from Earth) on the 9th.
The Moon passes within 1° of Aldebaran in the evening twilight on the 17th.
The whole of the total lunar eclipse on the morning of the 21st is visible from the UK. Totality lasts for just over
an hour, but to see the progress of the penumbral shadow you need to be up and running before 03:30. The whole
event lasts from 02:37 until 07:48.
The Planets
The only conspicuous planet in the evenings of January is Mars.
Mercury will start the month rising about an hour before the Sun. Mercury is only just above the ecliptic at
this time, and is 4° to 7° above the Horizon in the twilight. It is not well placed for observing, as always, be aware
of the rising Sun if you wish to take a chance! At this time of year the ecliptic is shallow at sunrise, and even low
down, the Sun can be quite dangerous to your eyesight. It rapidly closes in on the Sun from our perspective and
reaches superior conjunction on the 30th.
Venus is at greatest western elongation on the 6th, and is to be found in the south east before the morning
twilight. This is about the best time and position to observe Venus this year. A waxing crescent Moon sits
between Venus and Jupiter in the morning twilights of both the 1st and 31st Jan.
Mars appears culminating in the evening twilight at around 17:30 early in the month. It can be found in the
constellation of Pisces, about 40° above the horizon throughout; moving to the other side of the solar system and
diminishing in diameter. On the 12th a waxing crescent Moon escorts Mars for a photo-opportunity.
Jupiter can be found rising just before the Sun, low down in the morning twilight throughout January. It is
not well placed for observing. A waxing crescent Moon sits between Venus and Jupiter in the morning twilights
of both the 1st and 31st Jan.
Saturn is in conjunction with the Sun on the 2nd and is unobservable in January, except for the very last days
when it emerges briefly in the morning twilight. It is in opposition on the 9th July, so better observing to be had
later this year.
Uranus is best observed at the beginning of the month. It can be found in the constellation of Pisces at RA 1h
47m 8s, Declination 10º 28' 57". At a magnitude of 5.78 it may well be found with a good pair of binoculars. You
may also just see the planet’s cyan (blue-green) hue in a small telescope. Uranus usually has few features visible
at such a distance, so little else may be seen even with a larger amateur instrument or by astrophotography.
Neptune is best observed early in the month, low down in the south-west, early evening. It fades into the
evening twilight later in January. It can be found in the constellation of Aquarius all month, and on the 1st it will
be at RA 23h 2m 56s, Declination -7º 8' 59", at a magnitude of 7.92. A thin crescent Moon can be seen to
approach within 5° south of Neptune on the 10th at 18:30 making it slightly easier to find.
Meteors
One of the best showers seen from the UK, the Quadrantids can be seen from 1st to 6th January. The ZHR varies
between 40 and 110 (expected to be around 80), and is at its best observed around the early hours of the 4th, the
peak only lasts a couple of hours. The radiant, in northern Boötes, is circumpolar and lies towards the star Alkaid
in Ursa Major, in a part of the sky that once contained a constellation called Quadrans Muralis; the Mural
Quadrant! At about 40 km/s, these meteors are relatively slow, but brighten just after maximum with occasional
green, yellow or blue hues. This year the thin waning crescent Moon, below the horizon, renders this shower very
favourable. The Quadrantids’ associated parent body is not known for certain, however, 2003 EH1 is a contender.
Constellation Culminations from Usk
A celestial body or region of the sky is said to culminate when it crosses an observer’s meridian (an imaginary line
drawn overhead and through both poles). All other things being equal objects are usually best observed in this
position as the light from them travels through the least amount of atmosphere.
Constellation Convenient Culminations Midnight Culminations Observability
Cetus 19:00 Early January Late October Whole
Triangulum 19:00 Mid-January Late October Whole
Aries 19:00 Mid-January Early November Whole
Fornax 19:00 Late January Early November Unfavourable - partially hidden
Conditions apply as to the use of this matter. © D J Thomas 2018 (N Busby)
Perseus 19:00 Late January Mid-November Whole - at zenith upper culmination
Orion (Pronounced oh-RYE-un)
In Welsh Orion nm.
Astronomy Orion is a magnificent constellation, which stands out amongst the southern
stars in winter time. Finding Orion should be no problem; its stars are some of the most
familiar in all the heavens and lie due south at 22:00 in mid-January. The famous Orion's
Belt marks the centre of the constellation and helps us find other stars of interest. When
Orion is orientated in this way, follow the line of the belt south-easterly to find Sirius, the
brightest star in the night sky, and north-westerly to find the Pleiades nebula, a magnificent
open cluster.
As well as dominating the
winter sky with its size, and
definition of shape, Orion has
more to offer the observer than
most other constellations.
Observe the glorious red giant
Betelgeuse, the equally brilliant
blue-white giants, Rigel and
Bellatrix, and the nebulous
beauty of the Great Orion nebula
in the sword.
Orion's bright, right shoulder is
famously called Betelgeuse, one
of the largest and most luminous
of observable stars. Betelgeuse
is frequently described as the
‘Armpit of the central one’,
however modern authorities
suggest the name derives from
the Arabic Jad al-Jauza meaning 'Hand of al-Jauza’ (the Arabic name for
Orion). Betelgeuse, which lies about 640 light years away, is a red supergiant
with a luminosity some 100,000 times that of the Sun and a diameter 1,000
times that of the Sun. This star is reaching the end of its life and pulsates, both in size and brightness.
Another famous star in Orion is his left foot, Rigel, from Ar-risha’ meaning ‘the foot’. This bright star is different to
Betelgeuse as it shines blue rather than red. This is due to the surface temperature of the star, blue stars are much
hotter, and Rigel is about 16,000 ºK, whilst cooler Betelgeuse averages 2,700 ºK. Rigel is a multiple star system of at
least three stars, although you'd need a small telescope to separate them.
Take a look at the three stars that make
up the belt, the one on the right is known
as Mintaka, and the one on the left is
Alnitak. Both names derive from the
Arabic meaning 'the Belt'. Alnilam, the
central star means ‘The string of pearls’.
Even with the naked eye, it can be seen
that the central 'star' in the three 'stars'
marking the dagger hanging from Orion's
belt appears to be a fuzzy patch rather
than a star. This is the Orion Nebula
(M42), perhaps the most photographed
deep sky object in the heavens, a vast
nebula of gas and dust exquisitely lit by
the internal and surrounding stars. This is
a stellar maternity ward, in which more young stars will appear from
this wealth of cosmic matter during the next tens of millions years.
Take a pair of binoculars to this part of the sky, inside the nebula can be found a small, fascinating four-star asterism
known as The Trapezium.
There are many nebulous (cloudy) regions in and around Orion. Barnard's loop, the Horse
head and many other nebulae are all part of the huge molecular cloud situated in that part of
the sky. Unfortunately with the exception of the Great Orion Nebula, they are all quite
difficult to observe by eye. That is because the eye is not very sensitive to the wavelengths of
the emitted light. However modified digital SLR (internal filters removed) cameras are very
Conditions apply as to the use of this matter. © D J Thomas 2018 (N Busby)
sensitive to these wavelengths and photographing the nebulae with an ordinary camera lens is easier than you might
think.
In larger telescopes the semi-circular Bernard’s Loop and just a smidgen south of Alnitak, the Horsehead Nebula
present rewarding challenges for the observer. The prominent horse-head portion of the nebula is a popular target for
amateur astronomers. The Horse Head was first recorded in 1888 by Scottish astronomer Willamina Fleming on
photographic plate B2312 taken at the Harvard Observatory. The Horsehead Nebula is approximately 1500 light
years from Earth. It is one of the most identifiable nebulae because of the shape of its swirling cloud of dark dust and
gases, which bears some resemblance to a horse’s head when viewed from Earth. The Horsehead Nebula appears to be
a region devoid of stars, surrounded by a distinguishing cloud of stars. However, in reality, this is a dark molecular
cloud which is obscuring the starlight from the brighter nebula, IC 434, situated beyond it. It is a region within the
larger Orion molecular cloud of ionised atomic hydrogen called HII regions.
The Great Orion Nebula was the first such HII region (pronounced “H two”) discovered (1610). Such zones are
important star-forming regions and can readily be seen in other active galaxies because they tend to be very large. The
Horse Head, Great Orion and Running Man nebulae, to mention a few are examples of HII regions.
Associated with it and enveloping it is Barnard’s Loop, which can be seen extending from the centre of the picture,
around toward the bottom. Although it was named the ‘Orion Loop’ by E. E. Barnard, and then renamed in his honour
for its discovery, it was possibly detected by William Herschel in 1786.
Positioned about 1600 light years away and stretching several hundred light years across, there are a number of
speculations as to the origin of this huge bubble. It may be a supernova remnant or possibly it was formed by a series
of supernova explosions.
It could also have developed when a density wave, associated with the structure of the Milky Way, moved through the
Galactic disk. While difficult to observe visually, it can be effectively photographed on long exposures as can be seen
in the above (top) image by Nick Busby, chair of Usk Astronomical Society.
Many amateur astronomers use special ultra-high contrast filters (UHC) to enhance views of such regions. In particular
they emphasises ionised oxygen (OIII) which has a greenish colour. Although intended to be screwed onto the barrel
of the eyepiece they can also be held between the eyepiece and the eye and moved in and out to reveal the nebulae and
are highly recommended
The Orionid meteor shower can be seen emanating over the eastern horizon at about 11.00 pm between 16 th to 27th
October.
Myths
An ivory carving dated to around 35000 BCE seems to illustrate that the stars of Orion have
long been associated in the minds of humans, and by 4000 BC, over 6000 years ago, the
patterns of the Bull, Lion and Scorpion were first characterized in Mesopotamia. A belief that
Orion's name originated with the Sumerian sun-god Uru An.na, meaning 'light of the heaven' is
largely unsupported.
Babylonian star catalogues from the Late Bronze Age identify MULSIPA.ZI.AN.NA, "The
Heavenly Shepherd" or "True Shepherd of Anu" (Anu being the chief god of the heavenly
realms) as the most likely origin. This is one of two MUL.APIN cuneiform tablets
consisting of lists of astronomical data.
In 1100 BC Amenhotep produced a ‘Catalogue of the Universe’ listing five
constellations including Orion and the Great Bear. In mythology, the Orion region
has been associated with the human form since ancient times. In
Egyptian mythology, Sah (Orion) was syncretized with Osiris.
His consort was Sopdet, the goddess of the flood, personified by
the star Sirius. Both held an important role in Egyptian
mythology, and the corresponding deities were associated with
Osiris and Isis.
Sah was frequently mentioned as "the Father of Gods" in the Old
Kingdom Pyramid texts. Pharaoh was thought to travel to Orion
after his death.
It is in Greek myth we find a man of gigantic stature, unrivalled good looks and a hunting prowess celebrated
throughout the ancient world and named Orion. There are many legends and versions of legends regarding Orion.
He was, according to Eratosthenes, the son of Euryale and Poseidon and consequently could walk on water. One
day, on a visit to the island of Chios he fell in love with Merope, beautiful daughter of Queen Helike and King
Oenopion. Orion sought her hand in marriage and was promised this in return for ridding the island of the many
dangerous beasts that troubled the inhabitants.
Orion exercised his skills with great success against the wildlife of the island but Oenopion began to delay the
marriage by inventing more and more tasks for Orion to undertake. Eventually, in a fit of desperation and self-pity
Orion consumed a flask of his unwilling father-in-laws most potent wine. With his senses dulled by the wine,
Orion forced his intended to consummate the marriage prematurely. Incensed by this, Oenopion plied Orion with
even more wine until the great hunter was insensible, and then put out his eyes.
Orion sought the help of the oracles to regain his sight and was instructed to seek the morning sun. He set off with
his loyal crew of sailors for the east and docked at the Isle of Lemnos, where Vulcan, the gods' blacksmith, aided
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him. He gave him Cedalion, an apprentice, to sit on his shoulders and guide him to the furthest ocean, where he
found the sun god Helios. Orion appealed to Helios to restore his sight. His plea was granted and with his sight
restored Orion enjoyed a love affair with Eos, sister of Helios and goddess of the Dawn.
Eventually his desire for Eos was overtaken by his desire for revenge against Oenopion and Orion once more set
off on his journey. In Crete he met Diana, goddess of the moon and also an ardent hunter. They rejoiced in their
common love of hunting and Diana now accompanied Orion on the chase. However, their closeness caused great
concern to Apollo, Dianas' brother, who feared that his sister would become Orion’s next conquest, and he waited
for an opportunity to discredit the hunter.
Orion had one great weakness. He boasted injudiciously about his achievements and claimed that there was no
animal that he could not slay. Apollo seized his opportunity and repeated these boasts to Mother Earth. She was
not only annoyed at his wantonness, but also fearful that he would destroy all predators (as he had on the island of
Chios) and decided to halt his exploits by producing a monstrous scorpion under his feet, covered in armour so
thick that it could never be slain.
For the first and last time in his life Orion was totally defenceless and died from the sting of the terrible beast.
Diana was distraught at the loss of her friend and companion and begged the gods to allow her to immortalise
Orion among the stars. Her wish was granted and Orion was sent to the mid-heavens.
As a reward for conquering such a hero, the scorpion was also granted immortality, but was sent to the southern
skies so that the two enemies should not be seen in the sky at the same time, and Orion should not be reminded of
his ignoble defeat. To give the hunter some sport in his permanent abode the gods thoughtfully provided him with
Taurus the bull to fight, and Canis Major and Minor, his loyal hunting dogs for company.
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